iOS 内存泄漏， View Controller 的自定义 TabBar 失控分配

Question

我正在使用以下代码在两个选项卡之间切换:

-(void)switchPage:(UIButton *)sender{


    DLog(@"");
    DLog(@"child view controllers %lu", (unsigned long)self.childViewControllers.count);


    switch(sender.tag){
        case 0:{

            for(id object in self.childViewControllers){

                if([object isKindOfClass:[QuestionsVC class]]){


                    [questionsTab willMoveToParentViewController:nil];
                    [questionsTab.view removeFromSuperview];
                    [questionsTab removeFromParentViewController];
                    questionsTab = nil;

                }

            }

            questionsTab = [[QuestionsVC alloc] init];
            [self addChildViewController:questionsTab];
            [self.view addSubview: questionsTab.view];
            [questionsTab didMoveToParentViewController:self];
            [self.view bringSubviewToFront:tabBarView];
            [self drawGrayLineLayer];

            break;
        }

        case 1:{


            for(id object in self.childViewControllers){

                if([object isKindOfClass:[AnswersVC class]]){

                    [answersTab willMoveToParentViewController:nil];
                    [answersTab.view removeFromSuperview];
                    [answersTab removeFromParentViewController];
                    answersTab = nil;

                }

            }

            answersTab = [[AnswersVC alloc] init];
            [self addChildViewController:answersTab];
            [self.view addSubview: answersTab.view];
            [answersTab didMoveToParentViewController:self];
            [self.view bringSubviewToFront:tabBarView];
            [self drawGrayLineLayer];

            break;
        }

}

奇怪的是， Root View Controller (选项卡栏)的子 VC 计数保持不变，而没有 subview Controller 被释放。

问题是什么？

下面是一个仪器快照，告诉我每次代码运行时每个 View Controller 都会重新分配，而旧的不会被释放。

Answer 1

我遇到的问题是我从 subview Controller 中初始化了其他对象，这些对象随后具有委托(delegate)属性，并且该委托(delegate)是 strong 因此对象保留了其父对象，即委托(delegate)—— viewcontroller，它创建了保留循环。

根据我所学，代表应该几乎总是弱(或者几乎从不强)